#!/bin/sh
set -eu

: "${PGHOST:?required}"
: "${PGUSER:?required}"
: "${PGDATABASE:?required}"
: "${PGPASSWORD:?required}"

psql -v ON_ERROR_STOP=1 -c '
  CREATE TABLE IF NOT EXISTS schema_migrations (
    version text PRIMARY KEY,
    applied_at timestamptz NOT NULL DEFAULT now()
  )
'

for migration in /migrations/*.up.sql; do
  version=$(basename "$migration" .up.sql)
  case "$version" in
    *[!0-9A-Za-z_-]*) echo "invalid migration name: $version" >&2; exit 1 ;;
  esac
  applied=$(psql -v ON_ERROR_STOP=1 -Atc "SELECT count(*) FROM schema_migrations WHERE version='$version'")
  [ "$applied" = 1 ] && continue
  {
    printf 'BEGIN;\nSELECT pg_advisory_xact_lock(731006);\n'
    cat "$migration"
    printf "\nINSERT INTO schema_migrations(version) VALUES ('%s');\nCOMMIT;\n" "$version"
  } | psql -v ON_ERROR_STOP=1
done